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Education / Training Not a Feinwerkbau sight

Not a Feinwerkbau sight

This report covers:

  • Not a fake
  • What we know
  • Comparison
  • Raw threaded hole
  • Oh, boy!
  • Why this report?

Several weeks ago I mentioned that the sight that came on the FWB 600 single stroke target rifle is a fake. Today I will tell you the rest of the story.

Not a fake

It’s possible that this sight is not really a fake that’s meant to deceive. Clearly it’s not a sight made by Feinwekbau, and I’m going to show you how I can tell, but it may be marked FWB just to alert the user what rifle it belongs on. Let’s see.

Fake sight
Note that the company name Feinwerkbau isn’t written on the fake sight — just the initials FWB. And note that they are engraved. Feinwerkbau didn’t engrave their initials on sights. They cast their entire name in raised letters!

So I went to eBay and found a period FWB rear target sight for a reasonable price. I could see that this one was genuine, so I bought it for the 600 and I hope it works.

FWB sight eBay
The markings on a period Feinwerkbau target sight purchased on eBay.

FWB sight 300S
The markings on my FWB 300S sight.

FWB 110 sight
The markings on my FWB 110 rear sight. They are the same as those on the eBay sight.

What we know

We know that the FWB 110 didn’t last long in the FWB stable of target rifles. That makes its rear sight that’s pictured above contemporary with the FWB 150 that predated the FWB 300. So the sight I bought on eBay is an early rear sight. Hopefully that won’t make a big difference.


Putting the two sights (the fake sight and the real one I bought on eBay) side-by-side we can see some differences. First, the real FWB sight is longer. I will call the other sight a fake throughout the rest of this report, but only to differentiate it from real FWB sights.

FWB two sights
The real Feinwerkbau rear sight on top, the fake below.

FWB two sights
A side view of both sights with the real FWB sight on the bottom.

The real FWB sight has index numbers on the side of the adjustment knobs. The fake has them on top.

FWB sights indices
The real FWB sight adjustment knobs have numbers on their sides (left in this picture). That’s the older sight I bought on eBay. The fake has numbers on top of the knobs. My FWB 300S sight also has numbers on top of the knobs.

Raw threaded hole

The thing that tipped me off that this sight wasn’t real was an open threaded hole in the left side of the main body. The hole is raw and not the workmanship of a company like Feinwerkbau.

FWB fake raw hole
You’re never going to find a raw threaded hole like that on anything made by Feinwerkbau.

Stock up on Air Gun Ammo

Oh, boy!

And then it happened. I looked at the peephole on the real FWB sight that was purchased on eBay and I saw that it was screwed into a threaded adaptor. I wondered whether the threads of the hole the adaptor was screwed into were the same size, pitch and threads per inch as the threads on the peephole of the new Crosman Precision Diopter rear sight. And the result is — drum roll please — the adaptor hole on the old FWB rear sight is the same size as the male threaded portion of the Crosman peephole, but the adaptor threads appear to be fine while the Crosman Peephole threads are coarse. So the Crosman peephole can be screwed into the FWB rear sight adaptor hole, but only a little way. And the FWB adaptor does not want to screw into the new Crosman sight. 

The bottom line is — we still don’t have a way to change the peephole on the new Crosman rear sight. But old or new, all FWB rear sight peepholes interchange, plus the AirForce target sight peephole threads into the FWB adaptor hole. That means that all those sights can use standard target sight accessories!

FWB peephole and adaptors
The new Crosman peephole (left) does not fit the FWB adaptor hole. The diameter is right but the thread count is different.

Why this report?

I’ve taken the time to show you the details of this rear sight to illustrate all that goes into something seemingly simple like mounting a rear sight on a target rifle. There is more to it than the sight just fitting on the sight base of the rifle. The adjustment range has to work with the front sight and, in today’s report, the interchangeability of peepholes, which we now understand also means all the aftermarket accessories. 

We still don’t know if this rear sight will work on the FWB 600 — which is what this whole drill is about. That will be another test, and that test is the precursor for the shootoff between the FWB 300S and the FWB 600. Are we having fun yet?

author avatar
Tom Gaylord (B.B. Pelletier)
Tom Gaylord, also known as B.B. Pelletier, provides expert insights to airgunners all over the world on behalf of Pyramyd AIR. He has earned the title The Godfather of Airguns™ for his contributions to the industry, spending many years with AirForce Airguns and starting magazines dedicated to the sport such as Airgun Illustrated.

28 thoughts on “Not a Feinwerkbau sight”

    • Yogi,

      I guess you haven’t followed the FWB 600 report. The fake sight failed to adjust enough to place the little round holes where they need to be. Hence this purchase of a sight that I hope will do that.


  1. B.B.,
    Reports like this are good in that they show that something “that’s so simple” can really open up a big can of worms. With airguns, it’s not always all sunshine and roses; sometimes seemingly simple things can get a bit tricky; and that’s when it’s best to do what you are doing here and “make haste…slowly.” 😉
    Looking forward to the rest of the story,

  2. BB: I’d appreciate being allowed to bring up the off topic discussion of the lowly, yet quite important Chronographs. As I research various web pages and blogs, such as this one, I come away feeling an intense need for one, but seem to be unable to search through the maze of technical information and the plethora of opinions available and come up with a reliable and simple to use Chronograph for my shooting needs.. The ones using Doplar technology, such as the FX model seems ideal, but your, as well as other’s writings about it are less than encouraging. The Bluetooth to Android technology sounds wonderful, until this is tried under real world conditions. I’m an Air gunner, not a computer technician. Some of the others , using light technology work, but are cumbersome for use in the field or even taking to the range on a regular basis. I state my case by concluding that I want a utilitarian tool to collate my arm’s information in a way that is usable in proving various items such as velocity, foot power at the muzzle, noise of shot pellet and perhaps one day, even figure the arc vs distance dilemmas. My main problem is that I want this now! I’m a 74 year old retired toddler that wants it all today . . . Now Wanagh! I just may through a tantrum.. Orvil

    • Doc,

      Ever since Shooting Chrony stopped making chronographs I haven’t had anything good to recommend. I DO NOT need to connect my chronograph to a computer or a phone. I just need a number. I’ll take care of the rest.


      • B.B.,

        My Competition Electronics ProChrono has worked very well for me for years. (They are lightweight plastic and are probably not durable, but I am careful with mine.)


      • I would recommend the Competition Electronics Pro Chrono DLX.with the Bluetooth technology built in. I have the previous model with the Bluetooth add on accessory. In a couple of informal side by side comparisons with a Shooting Chrony (I forget which model) the Pro Chrono was more reliable, with fewer error readings. We also compared the Pro Chrono with the Oehler 35p and got identical readings. The Pro Chrono stays attached to my tripod all the time so set up is simplified. Set target down range, adjust the rifle on the bags to align sights and set the tripod/Chrono for proper height.. I didn’t think I would like the Bluetooth. Like BB, I only need a number. But now, I would hate to be without it. The app is so easy to use.

        A couple of other pluses to Competition Electronics. We also use their shot timers. Again, products that just work like should. And lastly, they are made here in the US, not China.

    • Orvil,
      K.I.S.S.! Keep It Simple Son! I have a Caldwell, it works great. The ProChrono that Michael recommends works great. With either, you will need a cheap camera bipod. Fold it down and collapse the legs, throw it in a pack or bag and away you go.

    • Hoppalong Doc, I like, “…retired toddler that wants it all…” 🙂

      Re. Chronographs:
      I’ve used a relatively cheap and basic chinese one for many years. If I were to break it (shot the screen on previous Chrony) , the lazy person that I am, would get one that records the speeds and calculations on paper. I’ll try’n show you the size of my current chronograph box by uploading a picture.

      Alternatively, what do you, and others, think about the much smaller Combro cb-625 mk4 that attaches to the muzzle?

      Question to everybody :
      Is there a way to know whether the speed measurements of one’s chronograph are correct, or at least consistently incorrect?

      For example, using my handheld global positioning satellite device (smartphone), I discovered that the car’s speedometer consistently over-reads by four kilometres per hour (ie I can dial in 4 kmh more and still remain legal).

    • Hoppalong Doc

      Orvil you have me by one year so to respect my Elder if you have the money get the LabRadar. You don’t need to conect it to anything if you just scribe it from the built in display to a sheet of papyrus or a wax/clay slate. I will grant you that using the conectivity gets you much cooler data possibilities but you can go real simple or REAL complex.
      You might want to hire a tech savvy kid and hook them on shooting in the process.


      • SHOOTSKI: I’m intrigued by this Labradar Chronograph.. As I research it online, I find that it seems to be retailed through Police shooting ranges in our area. I see that Pyramyd doesn’t show it on their web page. From what I can see so far . . . I like it. Ebay has some listed, but I’m always reticent to engage in bidding wars over things like this. Thanks for the referral , Orv.

    • Orvil,

      I use the FX radar chronograph with an Apple phone that hasn’t had a software update since I got it 6 years ago. My radar works perfectly as long as I remember to set the range to the velocity I expect the gun to fall into. That and change the battery when the light comes on is all I do. Its great to use in bright or subdued light, even total darkness, if you want. It’s very compact and it talks to you as you shoot so you get the results without looking away from your gun. It works with BBs, Airsoft ammo, pellets and arrows. It would be my recommendation.


  3. B.B.,

    Just curious. Have you given all the FWB-esque sights and their parts a magnet test? Feinwerkbau might use alloy for their sights or not. but inconsistencies among the pieces might be revealing.

    Also, that sloppy mold mark in photo number 8 looks suspicious to me.


      • B.B.,

        I’m curious if some parts of one, the other, or both are steel while others are pot metal. Of course pot metal suggests cost savings, so it would be interesting if the “faux” Feinwerkbau (try to say that fast five times) sight were not steel. That’s all.


  4. BB,
    “shootoff between the FWB 300S and the FWB 600. Are we having fun yet?” – Hell yeah! When?!? Please tell me when?

    Regarding rear diopter sights – I have something which is not having any logo. I was told there were 3 main variants of diopter rear sights on FWB300S. I have one which is looking a bit different. It is working very fine and it is robust. Additionally it has some extansion to reduce side light.

  5. B.B.,
    The term you are looking for is OEM (Original Equipment Manufacturer) the rear sight that came with your rifle is a GENERIC device/replacement part and not a “fake” part.

    • shootski, please forgive me for my uninvited response, but…

      … I agree that the acronym for Original Equipment Manufacturer is a correct option to describe a genuine part (though I bet I was not the only one who had to look up the meaning, the first time I came across OEM).

      The bit I’m confused about, is the term ‘generic’ in this instance : you see, besides whether it’s ok or not to mislead with markings, the “FWB” stamped peepsight doesn’t even work as a generic replacement.

      I wonder, when do you think is something no longer ‘generic’ and what does it take to become ‘fake’?

      • hihihi,

        In my opinion I look at it like car parts. It is OEM if the manufacturers obtain their parts from them or if the part has been proven to be manufactured to specification. It is a fake if the part is branded as original and fails to perform to specification.


      • hihihi,

        No need to ask forgiveness!

        First: “The bit I’m confused about, is the term ‘generic’ in this instance : you see, besides whether it’s ok or not to mislead with markings, the “FWB” stamped peepsight doesn’t even work as a generic replacement.”
        Generic in my view is something that at least meets most of the OEM devices functionality. The “FWB” device could work with a front sight that enables POA and POI to meet at some distance (probably at 10 meters) but we have no idea that is true because we have no documentation or model/serial number matching to inform us. We have no idea who engraved those three letters in the rear sight and certainly have no idea of their intent in doing so.

        Second: it isn’t a facsimile. “Fac simile is a Latin phrase meaning “make similar.” English speakers began using facsimile as a noun meaning “an exact copy” in the late 1600s. In this sense,”. The Chinese make lots of facsimile airguns avoiding the licenses and Fees; some call them Knock Offs. I don’t think that’s what they are but the Rollex the guy on the corner in Peking tried to sell me was not the real Rolex™…did you realize the incorrect spelling of the trademark? Now that is what I call a FAKE.

        Hope that helps!


  6. BB,

    Attached is a picture of the sight that came with my FWB 10 meter rifles for your reference. I included the picture because my FWB 603 sight looks different from the ones you are showing.

    The loose sight is from my FWB 300S (now scoped) and included an aftermarket riser. The mounted sight is on my FWB 603.


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